This invention relates in general to rocket combustion chambers and in particular to a new and useful method of closing canals or cavities which are formed in the walls of combustion chambers or heat exchangers or similar components.
The invention relates in particular to a method to produce closed canals or other cavities provided in components such as heat exchangers or rocket combustion chambers, which canals or cavities are closed towards the outside by a metalloplastic cover in such a manner that after the insertion of elongated fillers of considerably smaller section than the canal or cavity section they are filled with a substance, in particular wax, which can be melted out and either is electrically conducting due to additives or is coated by an electrically conducting layer, whereupon the cover is galvanized on.
It is known from German PS No. 28 15 525 to close the longitudinal cooling canals worked into the base structure of a component such as a rocket combustion chamber with a galvanically produced cover layer. Toward this end, tubular fillers are inserted into the cooling canals before this cover layer is galvanized on, the filler section being considerably smaller than the cooling canal section. The remaining space is filled by an electrically conducting wax, whereupon the cover layer is galvanized on. Then the tubular fillers are flushed out or removed by a chemical solvent conducted through them. This creates cavities in the wax which perform the function of absorbing the wax expansions occurring due to heating during the subsequent wax melting operation, so that the wall structure remains unaffected by compressive forces, which means that the cover layer and its sensitive connections to the canal webs are not subjected to the expansion forces of the wax.
However, besides this noteworthyadvantage the known method has the disadvantage that the chemical removal of the numerous tubes located in the wax and serving as fillers is cumbersome, time-consuming and expensive.